Dental Radiographs

The two major risks to the developing fetus caused by excessive exposure to radiation are development of cancer and mental retardation. It appears that 10 microsieverts (µSv) of radiation is the level required for either effect to occur.22 With proper radiographic techniques and precautions, the amount of radiation exposure from dental x rays ranges for bitewing radiographs from 26 µSv (skin dose) 0 µSv (thyroid dose), and for full mouth series from 90-122 µSv (skin dose) to 117-550 µSv (thyroid dose). To put these values in perspective, background radiation from natural occurring sources is approximately 3,100 µSv annually.23 The fetus is most sensitive to the effects of radiation between the eighth and 15th weeks after conception, a period of major neuronal and organ development.24 Proper radiographic techniques, such as rectangular collimation, lead shielding (abdominal and thyroid), use of the fastest available films (E/F speed film or digital), use of a long cone and avoidance of retakes, ensure that radiation exposure to the pregnant patient and fetus is minimized. However, even with observance of these precautions, the dental x-ray beam may pass through or near the thyroid gland. The juvenile thyroid is very sensitive to radiation induced tumors, both benign and malignant. In addition, thyroid radiation exposure during pregnancy is associated with infant low birth weight. If dental treatment will be deferred until after delivery, so should dental radiographs.25,26

Patients who are reluctant to accept necessary radiographs should be explained the risk of complications is so low it is impossible to measure. There is more risk to the fetus associated with lack of dental care than in providing treatment that includes dental radiographs. Lack of radiographs allows for inaccurate diagnosis which may lead to pain and infection, which could ultimately harm the fetus. Providing treatment, such as endodontic therapy or extractions without radiographs, may be considered substandard treatment. Dental radiographs are an integral part of any dental examination or treatment.27

The following points should be discussed with the pregnant patient (adolescent and adult) as part of the consultation.

  • Pregnancy by itself is not a reason to postpone routine and necessary dental treatment.
    • Self-medication with over-the-counter medications to control pain may cause unforeseen harm to the pregnant patient and possibly to the fetus.
    • Untreated oral infection may become a systemic problem during pregnancy and may contribute to preterm and/or low birth weight deliveries.
    • Untreated cavities in mothers may increase the risk of caries in children.
    • An unhealthy dentition may affect the nutritional intake of the expectant mother and the availability of nutrients necessary for fetal growth.

  • Nutritional counseling includes:
    • Foods containing fermentable carbohydrates should be limited to mealtimes.
    • Eating small amount of foods throughout the day (to minimize nausea) and limit intake to non-cariogenic snacks is recommended.
    • Brush teeth daily with fluoride toothpaste.
    • Nausea and vomiting are common among pregnant females, so to neutralize acid after vomiting, pregnant females should rinse with a teaspoon of baking soda mixed in a cup of water or use a fluoride rinse and immediate brushing should be avoided.
    • Women should be advised about the high sugar content of over-the-counter antacids and the increased risk of caries with long-term use.
    • Proper maternal nutrition is important for both the expectant mother and fetus. Important nutrients include folate, vitamin B-6, vitamin B-12, calcium and zinc.

  • Caries prevention includes recommendations for reducing the maternal cariogenic bacterial load and increasing enamel resistance.
    • Recommend fluoride toothpaste along with fluoride mouth rinses.
    • Prescribe chlorhexidine mouth rinses and fluoride varnish, as appropriate.
    • Recommend the use of xylitol containing chewing gum.
    • Restoring existing carious lesions in the pregnant patient reduces the quantity of streptococcus mutans in the oral environment.28